MT#55283 extend "answer only" logic

Provide an extra codec-store for the lookup of the answer codec. This is
needed for codec switches during an extra answer, as the original codecs
are kept in a different codec-store.

Closes #2073

Change-Id: I7e2efc434789ecc8d3b5fcf97240e5c3f7c84652
(cherry picked from commit cfe9a588fa)

daemon/call.c

@@ -2563,21 +2563,21 @@ static void codecs_answer(struct call_media *media, struct call_media *other_med
 			STR_FMT(&other_media->monologue->tag),
 			other_media->index);
 
-	bool codec_answer_only = true;
+	const struct codec_store *answer_cs = &media->offered_codecs;
 	// don't do codec answer for a rejected media section
 	if (other_media->streams.length == 0)
-		codec_answer_only = false;
+		answer_cs = NULL;
 	else if (sp->rtp_endpoint.port == 0)
-		codec_answer_only = false;
+		answer_cs = NULL;
 
 	if (flags->reuse_codec)
 		codec_store_populate_reuse(&other_media->codecs, &sp->codecs,
 				.codec_set = flags->codec_set,
-				.answer_only = codec_answer_only);
+				.answer_cs = answer_cs);
 	else
 		codec_store_populate(&other_media->codecs, &sp->codecs,
 				.codec_set = flags->codec_set,
-				.answer_only = codec_answer_only,
+				.answer_cs = answer_cs,
 				.allow_asymmetric = !!flags->allow_asymmetric_codecs);
 	codec_store_strip(&other_media->codecs, &flags->codec_strip, flags->codec_except);
 	codec_store_offer(&other_media->codecs, &flags->codec_offer, &sp->codecs);
@@ -3811,12 +3811,13 @@ int monologue_subscribe_answer(struct call_monologue *dst_ml, sdp_ng_flags *flag
 		if (flags->allow_transcoding) {
 			codec_store_populate(&dst_media->codecs, &sp->codecs,
 					.codec_set = flags->codec_set,
-					.answer_only = true,
+					.answer_cs = &src_media->codecs,
 					.allow_asymmetric = !!flags->allow_asymmetric_codecs);
 			codec_store_strip(&dst_media->codecs, &flags->codec_strip, flags->codec_except);
 			codec_store_offer(&dst_media->codecs, &flags->codec_offer, &sp->codecs);
 		} else {
-			codec_store_populate(&dst_media->codecs, &sp->codecs, .answer_only = true,
+			codec_store_populate(&dst_media->codecs, &sp->codecs,
+					.answer_cs = &src_media->codecs,
 					.allow_asymmetric = !!flags->allow_asymmetric_codecs);
 			if (!codec_store_is_full_answer(&src_media->codecs, &dst_media->codecs))
 				return -1;

daemon/codec.c

@@ -5652,7 +5652,7 @@ void __codec_store_populate_reuse(struct codec_store *dst, struct codec_store *s
 			codec_store_add_raw_link(dst, dup, pos);
 		}
 		else {
-			if (!a.answer_only) {
+			if (!a.answer_cs) {
 				ilogs(codec, LOG_DEBUG, "Adding codec " STR_FORMAT "/" STR_FORMAT
 					" (%i) to end of list",
 						STR_FMT(&pt->encoding_with_params),
@@ -5732,8 +5732,11 @@ void __codec_store_populate(struct codec_store *dst, struct codec_store *src, st
 				GINT_TO_POINTER(pt->payload_type));
 		if (orig_pt && !rtp_payload_type_eq_compat(orig_pt, pt))
 			orig_pt = NULL;
-		if (a.answer_only && !orig_pt) {
-			if (a.allow_asymmetric)
+		if (a.answer_cs && !orig_pt) {
+			orig_pt = t_hash_table_lookup(a.answer_cs->codecs, GINT_TO_POINTER(pt->payload_type));
+			if (orig_pt && !rtp_payload_type_eq_compat(orig_pt, pt))
+				orig_pt = NULL;
+			if (a.allow_asymmetric && !orig_pt)
 				orig_pt = codec_store_find_compatible(&orig_dst, pt);
 			if (!orig_pt) {
 				ilogs(codec, LOG_DEBUG, "Not adding stray answer codec "

include/codec.h

@@ -160,9 +160,9 @@ void codec_update_all_source_handlers(struct call_monologue *ml, const sdp_ng_fl
 
 struct codec_store_args {
 	str_case_value_ht codec_set;
-	bool answer_only;
-	bool allow_asymmetric;
+	const struct codec_store *answer_cs;
 	struct codec_store *merge_cs;
+	bool allow_asymmetric;
 };
 
 __attribute__((nonnull(1)))